Upright vacuum cleaners have long been known in the art. Such vacuum cleaners generally include a nozzle assembly with a suction inlet and an optional rotary agitator. A handle assembly is pivotally connected to the nozzle assembly. The handle assembly usually includes the control handle or stalk and typically houses both the dirt collection vessel and the suction generator. However, either or both of the dirt collection vessel and suction generator may be provided on the nozzle assembly if desired.
In operation, the operator inclines the handle assembly and control handle from an upright storage position and pushes and pulls the vacuum cleaner to and fro over the surface to be cleaned. Generally, some effort is required to turn the vacuum cleaner left and right in order to guide it over the floor as necessary to complete the cleaning operation. This is particularly true in tight areas such as in room corners or when cleaning around furniture.
It has been recognized that it is desirable to reduce the effort required to turn and maneuver the vacuum cleaner during the cleaning operation. Several design modifications have been proposed to meet this end. One of the most recent, is disclosed in U.S. Pat. No. 7,600,292. Specifically, the upright vacuum cleaner is equipped with a roller assembly or ball instead of individual rear wheels. The roller assembly may be substantially spherical in shape with truncated faces at opposed ends. The curved outer surface causes the control handle to tilt to one side or the other to aid in turning the vacuum cleaner right or left as desired. While this design improves maneuverability, there are significant trade-offs. For example, the suction motor is positioned inside the roller assembly. This high speed motor produces substantial torque that interferes with the smooth turning operation of the device. Further, the resulting vacuum cleaner is somewhat unstable and requires a retractable stand to support the control handle and handle assembly in an upright storage position. The stand has a flimsy, awkward appearance and provides minimum functionality that does not inspire confidence in the user.
The present invention relates to a new and improved vacuum cleaner designed to provide enhanced maneuverability while avoiding detrimental performance tradeoffs associated with the prior art design. Advantageously, the maneuverability enhancements are achieved in a compact design of high reliability that may be produced at a competitive cost.